Comparative study of implicit and subgrid‐scale model large‐eddy simulation techniques for low‐Reynolds number airfoil applications

Garmann, Daniel J.; Visbal, Miguel R.; Orkwis, Paul D.

doi:10.1002/fld.3725

Cited by 152 publications

(75 citation statements)

References 51 publications

(94 reference statements)

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“…The filter is applied directly to the solution (conservative variables) at every time step and acts as an implicit sub-grid scale (SGS) model that enforces dissipation of scales smaller than the filter cut-off wavelength. Garmann et al (2013) performed an extensive analysis of the ILES technique in comparison to more conventional ones with an explicit SGS model and concluded that, subject to an appropriate grid resolution, ILES simulations are capable of correctly capturing the flow physics of a flow such as the one being studied in the current study.…”

Section: Problem Description and Methodsologymentioning

confidence: 94%

A large-eddy simulation on a deep-stalled aerofoil with a wavy leading edge

Pérez-Torró

Kim

2017

J. Fluid Mech.

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A numerical investigation on the stalled flow characteristics of a NACA0021 aerofoil with a sinusoidal wavy leading edge (WLE) at Re ∞ = 1.2×105 and α = 20• is presented in this paper. It is observed that laminar separation bubbles (LSBs) form at the trough areas of the WLE in a collocated fashion rather than uniformly/periodically distributed over the span. It is found that the distribution of LSBs and its influence on the aerodynamic forces is strongly dependent on the spanwise domain size of the simulation, i.e. the wavenumber of the WLE used. The creation of a pair of counter-rotating streamwise vortices from the WLE and their evolution as an interface/buffer between the LSBs and the adjacent fully separated shear layers are discussed in detail. The current simulation results confirm that an increased lift and a decreased drag are achieved by using the WLEs compared to the straight leading edge (SLE) case, as observed in previous experiments. Additionally, the WLE cases exhibit a significantly reduced level of unsteady fluctuations in aerodynamic forces at the frequency of periodic vortex shedding. The beneficial aerodynamic characteristics of the WLE cases are attributed to the following three major events observed in the current simulations: (1) the appearance of a large low-pressure zone near the leading edge created by the LSBs; (2) the reattachment of flow behind the LSBs resulting in a decreased volume of the rear wake; and, (3) the deterioration of von-Kármán (periodic) vortex shedding due to the breakdown of spanwise coherent structures.

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Section: Problem Description and Methodsologymentioning

confidence: 94%

A large-eddy simulation on a deep-stalled aerofoil with a wavy leading edge

Pérez-Torró

Kim

2017

J. Fluid Mech.

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“…SVV and low-pass filtering can also be used to address the closure problem, i.e. by introducing artificial dissipation to represent the effect of the subgrid scales [20,[24][25][26][27][28]. A technique intended solely for stabilization of high-order schemes is over-integration, also known as polynomial de-aliasing, but this incurs a high computational cost [9,29].…”

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confidence: 99%

Simulation of the Taylor–Green Vortex Using High-Order Flux Reconstruction Schemes

Bull

Jameson

2015

AIAA Journal

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“…23 The filtering regularization procedure provides an attractive alternative to the use of standard SGS models, and has been found to yield suitable results for several turbulent and transitional flows on LES level grids. 24 A reinterpretation of this ILES approach in the context of an Approximate Deconvolution Model 25 has been provided by Matthew et al 26 III. Numerical procedure All simulations were performed with the extensively validated high-order, Navier-Stokes flow solver, FDL3DI .…”

Section: Governing Equationsmentioning

confidence: 98%

Transient Encounters of a NACA0012 Wing with a Streamwise-Oriented Vortex

Garmann

Visbal

2015

45th AIAA Fluid Dynamics Conference

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A high-fidelity numerical study has been conducted to examine the unsteady interactions resulting from a finite wing maneuvering into a streamwise-oriented vortex as a representative problem of wake encounters. A NACA0012 wing at an angle of α = 4 • and operating at a Reynolds number of Re = 2.0 × 10 5 is dynamically maneuvered into the path of a stationary vortex, and the transient encounter is analyzed for three side-slip velocities corresponding to 10%, 20%, and 40% of the free stream. The wing is shown to traverse a range of flow regimes, including instances of vortex pairing of the tip and incident vortices that lead to mutual induction and attenuation of the pair, tip vortex suppression as the impingement passes inboard of the wingtip, and induced separation that precipitates an abrupt transition at the leading edge. The overall flow structure is mostly consistent among the wing speeds examined, indicating an almost quasi-stationary response with relative vortex position. However, a notable lag is observed in the development of a spiraling instability in the incident vortex just upstream of the wing. With slower encounter speeds, the vortex core exhibits a pronounced spiraling undulation that persists farther upstream earlier in the motion. The advanced development is attributed to prolonged exposure to the adverse pressure gradient from stagnation on the underside of the wing that decelerates the core axial flow below known stability bounds of the vortex. Additionally, a dynamic loading effect is identified prior to the vortex crossing inboard of the wingtip, whereby the incident structure's relative position at peak loading shifts outboard with increased wing speed. The peak magnitudes of lift, pitching moment, and rolling moment coefficients are also shown to scale proportionally with the wing's side-slip speed as they are predicated upon an enhanced tip vortex development. In all cases as the wing approaches the vortex, an upstream progression of separation, transition, and reattachment over the leading edge leads, which forward tilts the force vector and reduces the drag. Once the vortex is brought inboard, however, the drag saturates, and the other quantities exhibit a nearly quasi-stationary response with vortex position as the wingtip unloads.

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Comparative study of implicit and subgrid‐scale model large‐eddy simulation techniques for low‐Reynolds number airfoil applications

Cited by 152 publications

References 51 publications

A large-eddy simulation on a deep-stalled aerofoil with a wavy leading edge

A large-eddy simulation on a deep-stalled aerofoil with a wavy leading edge

Simulation of the Taylor–Green Vortex Using High-Order Flux Reconstruction Schemes

Transient Encounters of a NACA0012 Wing with a Streamwise-Oriented Vortex

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